(1) Field of the Invention
The present invention relates to liquid crystal display devices and, more particularly, to a liquid crystal display device in which a color filter and active elements are placed on one identical substrate side.
(2) Description of the Related Art
For liquid crystal display devices in which a color filter and a black matrix are provided on an upper substrate while interconnect lines and active elements are provided on a lower substrate with liquid crystals interposed therebetween, there is a great difficulty in achieving positional alignment, more often incurring color mixtures and decreases in the numerical aperture.
In order to solve such problems, there has been used a COA (Color filter On Array) method in which a color filter and active elements are formed on one identical substrate.
PTL 1 (JP 2002-350886 A) describes a display device in which in a one-side substrate, a color filter is provided on a protective film for active elements, and contact holes are formed in the protective film for the color filter and the active elements so as to allow one pixel electrode and another pixel electrode of the active elements to be connected to each other.